node_map.h

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/*
 * Copyright 2026 The A11 Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#ifndef A11_NODES_NODE_MAP_H_
#define A11_NODES_NODE_MAP_H_
 
#include <cstddef>
#include <functional>
#include <memory>
#include <string>
#include <string_view>
#include <vector>
 
#include <absl/base/thread_annotations.h>
#include <absl/container/flat_hash_map.h>
#include <absl/status/status.h>
#include <absl/status/statusor.h>
 
#include "thread/boost_primitives.h"
 
namespace a11::stores {
class ChunkStore;
}  // namespace a11::stores
 
namespace a11::nodes {
 
class AsyncNode;
 
using ChunkStoreFactory =
    std::function<absl::StatusOr<std::shared_ptr<stores::ChunkStore>>(
        std::string node_id)>;
 
class NodeMap : public std::enable_shared_from_this<NodeMap> {
 public:
  static absl::StatusOr<std::shared_ptr<NodeMap>> Create(
      ChunkStoreFactory factory = {});
  ~NodeMap() = default;
 
  // By value: on a miss the id is moved into the map, and callers hand it
  // over rather than lending it.
  // NOLINTNEXTLINE(performance-unnecessary-value-param)
  absl::StatusOr<std::shared_ptr<AsyncNode>> Get(std::string node_id);
 
  absl::StatusOr<std::shared_ptr<AsyncNode>> GetIfExists(
      std::string_view node_id) const;
 
  absl::StatusOr<std::shared_ptr<AsyncNode>> Discard(
      std::string_view node_id,
      const std::shared_ptr<AsyncNode>& expected = nullptr);
 
  [[nodiscard]] bool Contains(std::string_view node_id) const;
 
  [[nodiscard]] size_t Size() const;
 
  [[nodiscard]] std::vector<std::string> Ids() const;
 
 private:
  explicit NodeMap(ChunkStoreFactory factory);
 
  const ChunkStoreFactory factory_;
  mutable thread::Mutex mu_;
  absl::flat_hash_map<std::string, std::shared_ptr<AsyncNode>> nodes_
      ABSL_GUARDED_BY(mu_);
};
 
}  // namespace a11::nodes
 
#endif  // A11_NODES_NODE_MAP_H_